The other cast members weren’t slouches either. One day, during a particularly intense confrontation between McCoy and Spock, DeForest Kelley leaned forward and kissed Leonard Nimoy on the nose. Leonard just stared at him, shocked, then realized what he had done and broke up.
But it didn’t end there. They couldn’t do a retake. Every time Leonard got close to DeForest and looked him in the eye, he broke up laughing again. And the effect was contagious. Pretty soon no one on the set could keep a straight face. Leonard and De were too conscious of their nose-to-nose position, they couldn’t stay in character long enough to do the shot. Finally, Joe Pevney, the director, gave up. They had to move to another set and pick up some other shots